Robins D M, Samuelson L C
Department of Human Genetics, University of Michigan Medical School, Ann Arbor 48109.
Genetica. 1992;86(1-3):191-201. doi: 10.1007/BF00133720.
Transposable elements, and retroviral-like elements in particular, are a rich potential source of genetic variation within a host's genome. Many mutations of endogenous genes in phylogenetically diverse organisms are due to insertion of elements that affect gene expression by altering the normal pattern of regulation. While few such associations are known to have been maintained over time, two recently elucidated examples suggest transposable elements may have a significant impact in evolution of gene expression. The first example, concerning the mouse sex-limited protein (Slp), clearly establishes that ancient retroviral enhancer sequences now confer hormonal dependence on the adjacent gene. The second example shows that within the human amylase gene family, salivary specific expression has arisen due to inserted sequences, deriving perhaps from a conjunction of two retrotransposable elements.
转座元件，尤其是类逆转录病毒元件，是宿主基因组中丰富的潜在遗传变异来源。在系统发育上不同的生物体中，许多内源基因的突变是由于元件的插入，这些元件通过改变正常的调控模式来影响基因表达。虽然已知随着时间的推移很少有这样的关联得以维持，但最近阐明的两个例子表明，转座元件可能在基因表达的进化中产生重大影响。第一个例子涉及小鼠性别限制蛋白（Slp），清楚地表明古老的逆转录病毒增强子序列现在赋予相邻基因激素依赖性。第二个例子表明，在人类淀粉酶基因家族中，唾液特异性表达是由于插入序列产生的，这些插入序列可能源自两个逆转座元件的结合。
